XML (=Extensible Markup Language) is a language, which allows a structured description of the content of a document using XML schema language definitions. A more precise description of the XML schema language definition and the definition of XML structures, data types and content models this allows can be found in the references [1], [2] and [3].
The use of XML-based descriptions of data streams, in which the individual components of the data stream are described or identified according to their syntactic significance using BSD (Bitstream Syntax Description; see reference [4]), freely addressable gBSD (generic Bitstream Description; see reference [5]) units or in respect of adaptation possibilities, is known from the prior art (see reference [6]). These descriptions of the data stream are used to adapt the data stream by means of a generic processor with no knowledge of the data stream format. To this end the description of the data stream can first be transformed in an appropriate manner, with the data stream then being adapted based on the transformed description.
In the case of the descriptions of data streams known from the prior art, the generic processor must read the complete description for a transformation of the data stream description or an adaptation of the data stream, in order to determine the necessary adaptations in the data stream description or in the data-stream. This is disadvantageous, as enough memory has to be made available for this in the generic processor and at the start of the adaptation it is necessary to wait until the processor has received the complete description of the data stream. This is a fundamental problem in the case of broadcast services, for example digital television, in particular.